I know there’s threads on old tires change out after x amount of time on every day tires but got me thinking. Not that they’re going on any time soon but I’ve got a set of snow tires that I’ve had since 2012 and a lot of tread left. They haven’t been mounted on the car since the end of 2014/15 season but when should I look at them being too old. Condition by the eye looks great with never any curbing to them.